In a take-up reel for metallic filament provided with a flange on both sides of the winding drum, the following can be given as a general example of a conventional structure for securing the end part of the metallic filament when the metallic filament is fully wound up on the reel. A small hole is provided in the outer circumference of the flange, and an end retaining member composed of steel wire, a plate spring, or the like is provided on the surface of the outer circumference of the flange in the vicinity of the small hole. The end part of the metallic filament is led through the small hole and is then sandwiched between the end retaining member and the outer surface of the flange. However, in such a case, the operation for passing the end part of the metallic filament through the small hole is troublesome, as is the operation for removing the end part when releasing the metallic filament. In particular, with steel cord used in tires, steel cord is typically unwound from more than 500 reels during the rubber coating process (calendaring process), one of the intermediate processes in tire manufacturing; it takes an inordinate amount of time to release the end parts of the steel cord from the end retaining members of such a large number of reels. Furthermore, if the metallic filament is a stranded wire such as steel cord or wire rope, there is a problem in that the end part frays and becomes difficult to pass through the small hole; for this reason, it is necessary to wind the end part in tape or weld the strands to one another through fusion in advance, which has been a very complicated process.
In order to solve the abovementioned problems, there has been proposed a reel onto which is attached an end retaining member capable of protruding from and receding into an access hole formed in a flange, the end retaining member having a catcher for retaining the end of the metallic filament at the tip thereof (see, for example, Patent Document 1).
This reel causes the end retaining member to elastically change in shape by applying pressure on the end retaining member in the outside-to-inside direction of the outer end surface of the flange, pushing only the catcher into the access hole; after the end part of the metallic filament is engaged with the catcher, the pressure is released, trapping the end of the metallic filament. With this kind of reel, the end part of the metallic filament does not need to be passed through a small hole, which eliminates the trouble of removing the end part from the small hole at the time of releasing, leading to an improvement in operational efficiency. However, with this type of reel, the end retaining member attached to the outer end surface of the flange protrudes significantly from the outer surface of the flange, which causes a problem in that the end part of the metallic filament dislodges from the end retaining member due to the end retaining member being pushed when the reel flange makes contact with another reel flange during the packaging and transport process for reel products, or when reels are stacked upon one another.
Accordingly, there has been proposed a reel in which a recessed portion is formed in the inner surface of the flange in a radial direction so as to extend to the flange outer edge, and a metallic filament end retaining member composed of a tabular metallic plate is provided so as to be embedded in the recessed portion; the end part of the metallic filament is grasped between the recessed portion of the flange and the end retaining member (see, for example, Patent Document 2).
However, with this type of reel, there is the possibility that the metallic filament enters into the space between the base end of the end retaining member and the bottom of the recessed portion, and becomes caught on the end retaining member at the time of releasing, causing problems such as breakage of the metallic filament.
Moreover, when retaining the end part of the metallic filament, the end retaining member enters a bent state, with its point of support being the portion of the end retaining member that is anchored to the end retaining member base end portion; this concentrates stress on this anchored portion, which generally uses spot welds and thus has decreased strength and tenacity due to the influence of heat. For this reason, problems such as plastic deformation, or, in a worst-case scenario, the end retaining member itself breaking, have arisen due to the bending of the end retaining member.
Further still, as stated above, spot welds are generally used for the anchored portion due to a strong anchoring force being required; however, with spot welding, the vicinity of the spot welds are annealed by the heat of the welding, causing a problem in that the amount of pressure that presses the end part of the metallic filament in the direction of the recessed portion in the flange drops, which in turn makes it impossible to retain the end part of the metallic filament with certainty.
Generally speaking, reels for taking up metallic filament such as steel wire, steel cord, wire rope, electrical wire, and the like are not single-use, disposable items, but rather can be repeatedly used any number of times, and thus the abovementioned problems present a major drawback in that they significantly shorten the lifespan of the reel.
As a solution for these conventional problems, there has been proposed a take-up reel for metallic filament in which a recessed portion is formed in the inner side of the flange in a radial direction so as to extend to the flange outer edge, the recessed portion having an attachment hole at its base; a tabular end retaining member having elasticity is fitted into the recessed portion, and the end retaining member base end portion is butted against the outer side surface of the flange and anchored (see, for example, Patent Document 3).
With this type of reel, the end retaining member base end portion that anchors the end retaining member extends to the outer periphery of the flange from the attachment hole in the base of the recessed portion, the recessed portion being provided in the radial direction extending to the flange outer edge; therefore, there is no space between the end retaining member base end portion and the recessed portion, which eliminates the conventional problem where the metallic filament enters thereinto at the time of releasing.
Furthermore, with this type of reel, when metallic filament has been fully wound upon the reel, the end part of the metallic filament is grasped between the end retaining member and the flange, with the end part of the metallic filament being secured by pressure arising from the elasticity of the end retaining member. Here, the force acting on the end retaining member has the portion where the attachment hole and the end retaining member make contact with one another as its point of support, meaning that the end retaining member is in a state where it is bent central to this portion. Thus, even if the elastic region drops due to the influence of heat in the vicinity of the end retaining member base end portion during spot welding, the pressure in the direction that presses the end part of the metallic filament does not decrease, making it possible to retain the end part of the metallic filament with certainty.
Further still, with this type of reel, the end retaining member is bent with the portion where the attachment hole and the end retaining member make contact with one another as the point of support, making it possible to avoid concentrating stress on the anchored portion; this in turn makes it possible to prevent plastic deformation, and reduces the possibility of the end retaining member dislodging due to breakage. Hence, the reel can be used repeatedly. Moreover, at the time of releasing, the metallic filament can be released simply by firmly pulling the end part of the metallic filament in an upward direction.
[Patent Document 1] JP H6-107377A
[Patent Document 2] Japanese Application for Utility Model Registration No. 3004340
[Patent Document 3] JP H9-263360A